Liquid crystal displays are commonly used as display devices for compact electronic apparatuses, because they not only provide good quality images but are also very thin. A verticality examining apparatus is generally needed for achieving accurate white balance of each liquid crystal display in mass manufacturing of liquid crystal displays.
Referring to FIG. 7, a typical verticality examining apparatus 7 for a liquid crystal display includes a locating member 71 and a supporting member 72 supporting the locating member 71. The locating member 71 includes a base 73, a tall locating arm 74, and a short locating arm 75.
The base 73 includes a bar-shaped main arm 731, and two subsidiary arms 733 perpendicularly extending in a same direction from respective opposite ends of a long side of the main arm 731. The main arm 731 includes two pairs of sliding channels 7312 located at opposite ends thereof respectively. The tall locating arm 74 can slide along a first pair of the sliding channels 7312, and the short locating arm 75 can slide along a second pair of the sliding channels 7312. The short locating arm 75 includes a first reference surface 751. The tall locating arm 74 includes a second reference surface 741 coplanar with the first reference surface 751, and a third reference surface 743 perpendicularly connecting with the second reference surface 741. Thus the second and third reference surfaces 741, 743 cooperatively define an essentially rectangular corner.
Referring also to FIG. 8, an operation of examining the verticality of a liquid crystal display 76 by using the verticality examining apparatus 7 is typically as follows. Front portions (not labeled) of the liquid crystal display 76 are positioned to contact the first and second reference surfaces 751, 741, and a right side portion (not labeled) of the liquid crystal display 76 is observed by a human operator as to whether it sufficiently contacts the third reference surface 743 or not. Thereby, the verticality of the liquid crystal display 76 is assessed, and a determination is made as to whether the verticality is satisfactory or not.
In summary, the verticality of the liquid crystal display 76 is determined by observing whether the side portion of the liquid crystal display 76 sufficiently contacts the third reference surface 743 or not. This process involves manual work, and relies on a human operator's judgment. The process is somewhat inefficient, and may result in an inaccurate observation or an incorrect determination being made.
What is needed, therefore, is a verticality examining apparatus that can overcome the above-described deficiencies.